Sheave block with self-locking track slide



Nov. 9,' 1948. R. Y. BARKLEY SHEAVE BLOCK WITH SELF-LOCKING TRACK SLIDE Filed Dec. 26, 1947 ul l lllm Attorneys Patented Nov. 9, 1948 SHEAVE BLOCK WITH SELF-LOCKING TRACK SLIDE Robert Y. Barkley, Weems, Va. Application December 26, 1947, Serial No. 793,977

Claims. (01. 114-111) This invention relates to a sheave block for marine and general industrial uses, and in its particular relation to certain marine applications, it relates to the combination of the sheave block with a self-locking track slide.

One of the objects of the invention is the provision of a sheave block tethered by an eye in which the movements of the block with respect to the eye both in a direction longitudinally of the axis of the eye, and in the direction of rotary movement about said axis, are restricted, so that when the rope which passes through the block becomes slack, the block cannot fall or turn relative to the eye, to a position in which the rope can become fouled, or in which the block can present any force thereof other than the sheave for engagement by the rope when the latter is drawn taut.

Another object of the invention is to provide a sheave block of the class described, in which the frame of the block encloses an opening large enough to permit the passage therethrough of a kinked or swollen rope or a knot or splice, and which has a perimetric contour smoothly convergent toward the sheave and presenting no shape or angular portions on which the rope can bind, chafe or be cut.

Still another object of the invention is the provision of a combined sheave block and selflocking track slide in which the pull upon the block fixes the track slide against further forward movement in the direction of the pull.

Other objects of the invention will appear as the following description of a practical embodiment thereof proceeds.

In the drawings which accompany and form a part of the following specification, and throughout the several figures of which the same reference characters denote identical parts:

Figure 1 is a front elevation of a sheave block embodying the principles of the invention;

Figure 2 is a section taken along the line 2-2 of Figure 1;

Figure 3 is a side elevation of the combined sheave block with self-locking track slide;

Figure 4 is a section taken along the line 4-4 of Figure 3;

Figure 5 is a diagrammatic view illustrating one use of the combined sheave block and selflocking track slide.

Referring now in detail to the several figures, the block which in general is designated by the reference character I, comprises an integral frame 2, in the form of a loop, preferably of pear shaped curvature, having its free end portions 3 parallel and spaced, closely embracing a sheave l, pivotally mounted therebetween. The sides 5 of the frame diverge symmetrically with respect to the medial diametrical plane of the sheave, the corresponding points adjacent the bight, at which points they are formed with enlargements 6 functioning as stops.

The bight is an arcuate portion 1, extending from stop to stop, also symmetrical with respect to said medial plane and of uniform cross-section throughout, being for the most part circular, with a projecting rib 8 extending circumferen tially along its outer side. The arcuate portion l is freely encompassed by an eye 9, having a keyhole shaped opening H3 therethrough, corresponding generally to the cross-sectional shape of the bight portion '5, including a narrow part H, which embraces and confines the rib 8. The opening H) is larger than said bight portion, giving freedom of limited universal movement of the block with respect to the eye, but inhibiting unrestricted rotation of the bight portion within said eye by virtue of the confinement of the rib 8 within the narrow part H of said opening. Said bight portion is slidable axially of the eye within the limits prescribed by said stops, the latter being too large to pass through the opening [0.

When the rope which passes through the block about the sheave becomes slack, the block can only fall sidewise to the extent indicated in Figure 1, in which the adjacent stop engages the eye 9, or to an equal extent in the opposite direction. The range of falling movement of the block in a forward and backward direction is limited by the engagement of the rib 6 with the sides of the narrow part l I of the opening Ill. In any of these limit positions, the sheave end of the block is always presented in the direction of that portion of the rope which leads to the object being pulled, so that when the rope is tightened, it will run on the sheave with no risk of being fouled upon the frame of the block. If when the rope becomes slack it falls away from the sheave and lies loosely within the opening 52 enclosed by the frame of the bloclz, it will be guided back onto the sheave when the rope is pulled taut by the convergent sides 5 of the frame The block can never over turn to such an extent as to present the bight portion of the block for engagement by the tightened rope.

The opening l2 of the frame is large enough to pass a kinked or swollen rope, a knot or loose splice, and the stops are rounded so that there is no angular irregularity in any part of the inner perimeter of the frame of the block which can cut, abrade the rope, or restrain its free movement. 1

The eye 9 is preferably swivelly mounted so that it can freely turn to bring the plane of rotation of the sheave into coincidence with the plane of the angle defined by the portion of the rope extending from the sheave to the object pulled and the portion from the sheave to the hand or other pulling instrumentality, so that the roperuns true in the sheave without frictionally engaging the sides of the frame adjacent the sheave.

To swivel the eye which carries the "block is a rather common expedient in the art. One way is suggested in Figures 1 and 2, in which the-eye 9 is mounted on a turntable I3, rotatable upon a fixed base l4.

Figures 3, a and 5 illustrate an adaptation of the sheave block as above described, in combination with a self-locking track slide for operating the jib sheet, in sailing. The numeral [-5 represent a standard track, a length of which is secured longitudinally of the deck on each side of the cockpit, as shown in Figure 5. The track has side flanges "I6 raised from the surface of the deck. The device of the present invention comprises a track slide ll, having a base I8 which rests upon the track, and having lateral inwardly facing channels l9 embracing the flanges I 6. The base 58 has an upstanding longitudinally extending'fin 2!).

A jam arm 2! is provided in the form of a rocking lever, the lower part of which is bifurcated and pivotally mounted astride the fin, the pivot 22 passing through the fin and through the upper part of the bifurcations 23. The length of said bifurcations from said pivot to their lower ends is somewhat greater than the perpendicular distance of the pivot from the track, and the base is cut away on both sides of the fin at 24, to permit the ends of the bifurcations to contact the flanges 26 cf the track.

When the jam arm is in contact with the track, it inclines slightly forwardly in a downward direction. When a pulling force is exerted forwardly upon the jam arm above the pivot 22, the lower ends of the bifurcations 23 jam against the track, locking the track slide ll against forward movement. It can be readily released so that it can be moved forward by pressing the upper end of the jam arm rearwardly against the pulling force. The track slide is freely slidable in a rearward direction. An emergency set screw 25 may be provided for positively locking the track slide against movement in either direction.

The eye 9 of the sheave block is at the end of a rectilinear shank 26, which is swivelly connected to the upper part 21 of the jam arm, passing freely through a hole in the latter. The swivel connection is formed between an integral enlargement 28 on the shank, and a nut 29, which screws onto the threaded end 3i! of said shank.

In Figure 5, in which the combined sheave block and track slide is employed to manipulate the jib of a sail boat, the device is duplicated on each side, two sheets extending from the part of the sail at the leech corner a, one passing through each block, one for each tack, one sheet being entirely free, while the other is in operation. In sailing close-hauled, the track slide is moved to forward position on the track to provide the minimum distance between the luff corner b, of the sail and the sheave block. Wind pressure upon the sail locks the track slide against further forward movement. When sailing more said rib with suflicient clearance to permit off the wind, the slide block is moved to a rearward position along the track and the sheet let out accordingly, thus increasing the distance from the luff corner to the block, permitting more fullness of the sail under wind pressure.

While I have in the above description disclosed what I believe to be a practical embodiment of my invention, it will be understood by those skilled in the art that the specificde'tails of construction and arrangement of parts, as shown, are by way of illustration and not to be construed as limiting the scope of the invention.

'What I claim as my invention is:

1. Sheave block comprising a frame in the form of a loop, a sheave closely embraced by the sides of said frame adjacent one end of said loop, rotatably mountedin said frame, the sides of said loop being mutually divergent from points adjacent said sheave to points adjacent the bight portion of said loop, an eye slidable on said bight portion for tethering said sheave block, and 'stop means on said frame for limiting the range of sliding movement of said eye along said bight portion.

2. Sheave block comprisinga frame in the form of a loop, a sheave closely embraced by the sides of said frame adjacent one end of said loop, rotatably mounted, the sides of said loop being mutually divergent from points adjacent saidsheave to points adjacent the bight portion of said loop, an eye slidable on said bight portion for tethering said sheave block, a rib on the outer side of said bight portion extending longitudinally thereof, saideye having a recess slidably embracing 'ited rotation of said sheave block aboutthe axis of said eye, and stop means on said frame for limiting the range of sliding' movement of said 'eye along said bight portion.

3. Slieave block comprising a frame in the form of a loop, a sheave closely embraced by thesides of said frame ad acent one end of said loop, pivotally mounted between said sides, the latter being mutually divergent from points adjacent said sheave to corresponding points adjacent the bight portions of said loop, enlargements of said sides at the ends of said bight portion, an eye slidable on said bight portion for tethering said sheave block, said enlargements functioning as stops to limit the range of sliding movement of said eye along said bight portion.

4. sheave block comprising a frame in the form of a loop, a sheave closely embraced'by' the sides of said frame adjacent one end of said loop, pivotally mounted between said sides, the latter being mutually convergent from points adjacent said sheave to corresponding points adjacent the bight portion of said loop, enlargements on said sides at the ends of said bight portion, an eye slidable on said bight portion for tethering said sheave block, said enlargements functioning as stops to limit the range of sliding movement of said eye along said bight portion, a rib onth'e outer side of said bight portion extending longitudinally between said enlargements, said'eye having a recess slidably embracing said rib with suificient clearance to permit limited rotation of said s eave block about the axis of said eye.

5. Sheave block as claimed in claim 4, includ ing a support, said eye being swivelly mounted relative to said support.

6. Sheave block comprising a frame in the approximate form of a pear shaped loop, a sheave embraced by the sides of said frame adjacent the small end of said he rotatably mounted limin said frame, the sides of said frame being mutually convergent from corresponding points adjacent the bight portion of said loop, to said sheave, for guiding a rope passing through said loop, to said sheave, an eye slidable on said bight portion for tethering said sheave block, and stop means on said frame for limiting the range of sliding movement of said eye along said bight portion.

7. Combined sheave block and locking track slide comprising a track slide having a base provided with side channels adapted to slidably embrace the lateral flanges of a track, an upstanding support on said base, a jam arm intermediately pivoted on said support, the length of the lower portion of said jam arm from its pivotal axis to its lower end being slightly greater than the perpendicular distance from said axis to the upper face of a track embraced by said track slide, whereby said jam arm is inclined forwardly in a downward direction while resting on said track, an eye bolt extending longitudinally of said track slide swivelly secured to the upper part of said jam arm extending forwardly thereof, and a sheave block tethered in the eye of said eye bolt, whereby pull on said sheave block jams said jam arm against said track.

8. Combined sheave block and locking track slide as claimed in claim 7, including means for limiting the sliding movement of said sheave block axially of the eye of said eye bolt as well as rotatable about the axis of said eye bolt.

9. Combined sheave block and locking track slide comprising a track slide having a base with side panels adapted to slidably embrace the lateral flanges of a track, an upstanding support on said base, a jam arm intermediately pivoted on said support, the length of the lower portion of said jam arm from its pivotal axis to its lower end being slightly greater than the perpendicular distance from said axis to the upper face of a track embraced by said track slide, whereby said jam arm is inclined forwardly in a downward direction when resting on said track, said base having an opening permitting contact of said jam arm with said track, an eye bolt extending longitudinally of said track slide swivelly secured to the upper part of said jam arm extending forwardly thereof, a sheave block tethered in the eye of said eye bolt, said sheave block comprising an arcuate bight portion slidable through the eye of said eye bolt and stops at the ends of said bight portion limiting the range of sliding movement of said sheave block relative to said eye bolt.

10. Combined sheave block and locking track slide as claimed in claim 9, including a rib on said bight portion extending from stop to stop, said eye bolt having a recess in the opening of its eye slidably embracing said rib with sufiicient lateral clearance to permit limited rotation of said sheave block about the axis of the eye of said eye bolt.

ROBERT Y. BARKLEY.

No references cited. 

